8.7-W average power, in-band pumped femtosecond Ho:CALGO laser at 2.1 µm
Weichao Yao, Yicheng Wang, Sergei Tomilov, Martin Hoffmann, Shahwar Ahmed, Christoph Liebald, Daniel Rytz, M. Peltz, Volker Wesemann, Clara J. Saraceno
Abstract
We report on an in-band pumped SESAM mode-locked Ho:CALGO bulk laser with a record-high average power of 8.7 W and an optical-to-optical efficiency of 38.2% at a central wavelength of 2.1 µm. At this power level, the bulk laser generates pulses with a duration of 369 fs at an 84.4-MHz repetition rate, corresponding to a pulse energy of 103 nJ and a peak power of 246 kW. To the best of our knowledge, this is the highest average power and pulse energy directly generated from a mode-locked bulk laser in the 2-3 µm wavelength region. Our current results indicate that Ho:CALGO is a competitive candidate for average power scaling of 2-µm femtosecond lasers.